The present invention relates generally to detoxification of hazardous materials and more particularly, to removal of organic compounds.
At this time there is a critical national need for removing trace amounts of toxic organic compounds from groundwater, surface water and industrial waste waters without transferring these compounds to the atmosphere or to burial sites. At present, oxidation by incineration or chemical means is the only method of accomplishing true detoxification rather than mere displacement of these organic toxins into the atmosphere or to another medium.
Incineration of dilute aqueous solutions of organic components is costly due to the energy required for the evaporation of water. Moreover, incineration may cause the formation of toxic by-products, such as dioxin derivatives, in the off-gases. Chemical oxidation processes to treat contaminated water include use of such substances as for example, potassium permanganate, chlorine dioxide, chlorine, hydrogen peroxide, or ozone. Additionally, oxidation may be enhanced using ultraviolet light (UV) in conjunction with any of these substances except permanganate.
Chemical detoxification methods are in commercial use for wastewaters and some ground waters. These methods present attendant disadvantages, however. For example, potassium permanganate produces manganese dioxide as a by-product during oxidation. Chlorine, and in some instances, chlorine dioxide, forms chlorinated organic compounds. Moreover, hydrogen peroxide plus ferrous sulfate (Fenton's reagent) produces a soluble and insoluble iron residue.
Ozonation without UV light partially oxidizes benzene derivatives to mono- and di-basic acids which are biodegradable, but does not oxidize saturated halogenated compounds. Oxidation with hydrogen peroxide and UV light is useful for oxidizing a number of organic compounds, but in many cases the rates of oxidation are significantly slower than when using UV/O.sub.3. While ozone combined with UV enhancement has been found to be cost-effective and practical for non-volatile unsaturated chlorinated hydrocarbons and a number of benzene derivatives, certain saturated chlorinated and oxygenated compounds, such as the pervasive pollutants methylene chloride and methanol, have been found to be refractory to UV-ozonation.
Thus there is a long standing need for a powerful and practical method for removing a wide spectrum of toxic organic compounds from water. Such a method should provide both a highly effective and cost-effective means of detoxifying hazardous compounds. The present application fulfills these needs and provides related advantages as well.